JP2553089B2 - Boiler soot blow control device - Google Patents

Description

Description: [Object of the invention] (Field of industrial application) The present invention relates to a soot blow control device for a boiler used in a boiler of a pulp manufacturing plant or the like, and particularly removes dust adhering to a heat transfer part. The present invention relates to a soot blow control device for a boiler, which has improved operation control means for the soot blow lance.

(Prior Art) In this type of pulp manufacturing plant, the black liquor discharged as waste liquid from the chip cooking process is burned in a recovery boiler to recover smelt, which is a raw material of a chemical used in the chip cooking process. , Has a system configuration that recovers steam using the combustion heat of black liquor. Specifically, the black liquor discharged as waste liquor from the chip cooking process is guided to the black liquor tank, and then the black liquor in the black liquor tank is heated by a heating unit (not shown) To spray. This jetted black liquor floats and dries to land on the bottom of the furnace to form a char bed. At this time, when the combustion air is sent into the boiler, the upper part of the char bed is combusted, and the combustion gas generated at that time passes through the heat transfer parts such as the super heater in the upper part of the furnace, the main bank in the exhaust gas passage line, and the economizer. And finally discharged from the chimney. The water sent from the water supply line in the exhaust gas passage line passes through the economizer, the main bank and the super heater, is heat-exchanged in these heat transfer parts, and is taken out as main steam. Further, in the furnace, the reduction reaction is carried out in a high temperature atmosphere on the char bed, so that sodium sulfate and the like in the black liquor become sodium sulfide, and the smelt as a raw material of the drug is recovered from the spoutro at the bottom of the boiler together with sodium carbonate and the like.

By the way, in the boiler as described above, dust generated during combustion of the char bed adheres to the heat transfer portion, which causes heat exchange efficiency to decrease with the passage of time. Therefore, in this type of plant, in order to remove dust adhering to the surface of the heat transfer portion, soot blow lances are attached to appropriate places including the boiler wall surface, etc. At that time, a drive control signal is sent to operate the soot blow lances one by one to remove dust.

As shown in FIG. 4, the soot blow control device receives the lance blowing order data, the time interval data and the subsequent change data S1 from an external operator,
The lance data registration unit 1 receives the data S1 and registers it in the table memory of the lance determination unit 2 or changes the already registered data. As a result, the table memory of the lance determining unit 2 stores the order, lance order data such as lance NO, and spray time interval data for each soot blow lance, as shown in FIG.

In such a state, when the timer 3 constantly measures the time and sends out the timer signal S2 at every predetermined time (for example, every one second), the lance determining unit 2 integrates the timer signal and the integrated time becomes the lance sequence. Data S coded (BCD) when the driving time of the next lance based on the data is reached
3 is sent to the soot blow start command unit 4. The soot blow start command unit 4 decodes the data S3 sent from the lance determining unit 2, and sends a drive control signal S4 to the soot blow lance obtained by this decoding to perform a blowing operation. This point will be explained with reference to FIG. 3 as an example.
First, drive the soot blow lance of lance NO.20, drive the soot blow lance of the next lance NO.26 after 10 minutes of this driving time, and continue driving the soot blow lance of the next lance NO.3 after driving the soot blow lance for 5 minutes. Drive the soot brow lance. Then, after the last soot brolan is driven for a predetermined time, the process returns to the beginning and similarly, each soot brolan is sequentially driven in accordance with a predetermined order and time interval.

Therefore, since the soot blow control device as described above drives and controls each soot blow lance in accordance with a predetermined time interval, even if a specific portion of the heat transfer portion is extremely dirty, it is possible to remove the dirt. It may end the drive in an insufficient time, which causes a significant decrease in the recovery efficiency of the boiler, and is also not preferable from the viewpoint of energy saving because the soot blow lance is drive-controlled at the same time interval every time even in a place with little dirt. .

(Problems to be solved by the invention) As described above, the conventional device is configured to drive and control a large number of soot blow lances at predetermined time intervals irrespective of the dirt state of each portion of the heat transfer portion. There is a problem that the amount of steam produced differs depending on the fouling state of the heat transfer section, or it is difficult to obtain a uniform chemical raw material, and the original function of the recovery boiler cannot be fully exerted. In addition, driving a lance that is not so dirty at regular time intervals, or driving the lance in an overload state where dust is completely adhered and stains cannot be removed poses a problem against energy saving.

The present invention has been made in view of the above circumstances, and appropriately drives and controls a large number of soot blow lances while appropriately changing the time interval of the soot blow lance according to the dirty state of the heat transfer portion, and the recovery function by the boiler is sufficient. It is an object of the present invention to provide a soot blow control device for a boiler, which can be effectively used and which greatly contributes to energy saving.

[Configuration of the Invention] (Means for Solving Problems) A boiler soot-blowing control device according to the present invention includes a time-measuring means for measuring time and a plurality of soot-blowing lance blowing order data and time interval data previously stored in a table memory. Is stored, and the signals from the timekeeping means are integrated,
When the integrated time reaches the time interval of the soot blow lance currently being driven, the soot blow drive control means for sending a drive control signal to the next soot blow lance based on the spraying order data, and the soot blow lance are installed at predetermined positions of the heat transfer section. Thermal efficiency calculating means for receiving a process signal from the generated sensor to obtain thermal efficiency, fouling coefficient determining means for determining a fouling coefficient of the heat transfer section based on the thermal efficiency calculated by the thermal efficiency calculating means, and fouling coefficient determining means The soot-blowing time interval determining means for changing the time interval data in the table memory of the soot-blowing drive control means is provided based on the stain coefficient determined in step 1.

As the soot blow drive control means, the signals from the time counting means are integrated, and when the integrated time reaches the time interval of the soot blow lance currently being driven, the soot blow lance NO to be driven next is coded. It has a configuration including a lance determining unit for outputting and a soot blow start command unit for receiving a code from the lance determining unit and giving a drive control signal to the soot blow lance of the soot blow lance NO corresponding to the code.

Further, as the soot blow time interval determining means, the dirt coefficient is converted into a time interval coefficient, and the time interval coefficient is multiplied by the time interval data to change to new time interval data for each soot blow lance. .

(Operation) Therefore, according to the present invention, by taking the above means, each soot blow lance is sequentially driven based on the spraying order data and the time interval data stored in advance in the table memory of the soot blow drive control means. Therefore, it is possible to prevent dust from adhering little by little over a long period of time to be completely solidified, that is, a state in which dirt cannot be removed. Moreover, after the thermal efficiency calculation means determines the thermal efficiency from the outputs of the sensors installed at various places of the heat transfer portion, the dirt coefficient determination means determines the dirt coefficient of the heat transfer portion from the obtained thermal efficiency, and further determines the dirt coefficient. Since it is converted into a time interval coefficient, the drive control of a large number of soot blow lances can be quickly changed under appropriate processing, and the recovery function of the boiler can be fully exerted, which in turn contributes greatly to energy saving of the boiler.

(Example) Hereinafter, one example of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a general pulp manufacturing plant equipped with a soot blow control device according to the present invention. In the figure, 11 is a recovery boiler installed as a part of a pulp manufacturing plant. In this boiler 11, black liquor A discharged as waste liquid from the chip cooking process is supplied to a black liquor tank 12 and a heating section (Fig. It is injected into the recovery boiler 11 by the injection gun 13 through a not shown). This jetted black liquor is suspended and dried in the furnace and falls to form the char bed 14. Combustion of this char bed 14 is promoted by the supply of combustion air B from the outside. At this time, a reduction reaction is performed in the high temperature atmosphere on the char bed 14 to make Glauber's salt (Na ₁ CO ₃ ) in the black liquor.
Becomes sodium sulfide (Na ₂ S), and smelt C, which is a raw material of the chemical used in the chip cooking step, is recovered from the spoutro 15 together with sodium carbonate (Na ₂ CO ₃ ) and the like. Further, the exhaust gas D generated by the combustion of the char bed 14 is discharged from the chimney 17 through the exhaust gas passage line 16.

Therefore, in order to effectively use the heat of the exhaust gas D,
A super heater 21 as a heater is provided above the boiler body, and a body bank 22 is provided in the middle of the exhaust gas passage line 16.
And an economizer 23 is provided, the water E supplied from one end side of the water supply line 24 is heat-exchanged through the heat transfer parts such as the economizer 23, the main body bank 22 and the super heater 21, and further passes through the main steam line 25. It is sent to the outside as main steam F.

Therefore, in the above boiler apparatus, the soot blow control device according to the present invention has the following configuration. First, soot blow lances 31a, 31b, ..., which blow out air or steam to predetermined portions of each component constituting the heat transfer portion in order to remove dust that obstructs heat exchange of the heat transfer portion such as the superheater 21 and the main body bank 22. Is provided. In addition, various measuring sensors are installed at necessary positions of the heat transfer unit in order to monitor the state of the process and judge the state of contamination. For example, a temperature sensor 32 for measuring the temperature inside the furnace, a steam flow meter 33 for measuring the steam flow rate, etc. are provided on the wall of the recovery boiler 11, or although not shown, an inlet temperature sensor on the input / output side of the super heater 21, An outlet temperature sensor may be provided. In addition, main unit bank 22 and economizer
Also in 23 and the like, for example, a temperature sensor for measuring the input / output temperature, a pressure measuring sensor for measuring the pressure difference between input and output, and the like are provided. The type of these sensors is not limited, but any type of sensor may be used as long as it is a sensor for obtaining the heat conversion efficiency as a standard for determining the dirt state. The output of each measurement sensor is introduced into the soot blow control device 40.

As shown in FIG. 2, the sootblow controller 40 includes a timer 41 for measuring time, a sootblow drive control means 42 for selectively driving and controlling a sootbrow lance by integrating a timer signal from the timer 41, and the measuring sensor. The soot blow drive control means 42 comprises a dirt state time determining means 43 for changing the lance drive time interval stored in the soot blow drive control means 42.

The soot blow drive control means 42 stores soot blow lance NO, time interval data, etc. based on a predetermined order, integrates the timer signal from the timer 41, and this integrated time is the time interval of the soot blow lance currently being driven. Has a function to send a drive control signal to the next soot blow lance according to the sequence data when it reaches the specified value. Specifically, it receives a request for changing the lance order or a request for changing the spraying time interval from the outside (operator). Lance data registration unit 44 that outputs change data for registration in order,
A table memory for storing sequence data such as lance NO and time interval data is provided, and the data in the table memory is changed based on the changed data from the lance data registration unit 44, and the timer signal from the timer 41 is also provided. Is calculated and whether the accumulated time is based on the sequence data, it is judged whether or not the time interval of the soot brow lance being driven has been reached.If it is judged that it has been reached, the next soot brow lance is determined and the lance NO is coded. A lance determining unit 45 for converting to a (BCD) signal and outputting the signal, and a soot blow start command unit for decoding the code signal from the lance determining unit 45 and sending a drive control signal to the soot blow lance corresponding to this code.
46.

Further, the dirty state time determining means 43 receives the process signal from the measurement sensors 32, 33, ... Installed at desired positions of the heat transfer section, and calculates, for example, the efficiency of the boiler, and the thermal efficiency calculating means. The boiler state determination unit 47 including a contamination coefficient determination unit that determines the contamination coefficient of the heat transfer unit based on the thermal efficiency obtained by the above, and the lance determination unit 45 based on the contamination coefficient obtained by the boiler state determination unit 47. And soot blow time interval determining means 48 for changing the time interval data of the table memory.

Next, the operation of the apparatus configured as described above will be described.
First, in the initial stage, when the operator inputs the sequence, the lance NO data, and the time interval data as the registration data S11, the lance data registration unit 44 receives the data S1 and sequentially stores the data S1 in the table memory of the lance determination unit 45. I will do it. FIG. 3 (a) is a diagram showing the data storage state at the initial stage. Then, the soot blow control device 40
When the soot blow lance drive start signal is received, the lance determining unit 45 converts the lance NO, 20 into the BCD signal S12 and sends it to the soot blow activating command unit 46. Here, the soot blow start command section 46 decodes the BCD signal S12 and sends a drive control signal S13 to the soot blow lance "20" corresponding to it, drives the soot blow lance "20" and blows out air, and the heat transfer section. Remove dust adhering to. During this lance drive period, the lance determination unit 45 integrates the timer signal S14 from the timer 41, and when the integration time reaches 10 minutes, selects the lance NO, 26 in the next order and similarly converts it to the BCD signal S12. Then, the soot blow start command unit 46 is sent to drive and control the soot blow lance “26”. Thereafter, the soot blow lance of the lance NO is driven for a predetermined time based on the sequence data shown in FIG. 3 (a) to perform the dust removing operation.

By the way, during the dust removal operation, the boiler state determination unit
47 is, for example, various process signals (draft, temperature, flow rate, etc.) S15 in the boiler are taken in every predetermined cycle by a measurement sensor installed at each desired position of the heat transfer unit, and the heat exchange efficiency is calculated based on the following formula. For example, the boiler efficiency η is obtained.

η = G · (h−h ₀ ) / (B · H) (1) However, in the above equation, G is the evaporation amount of the boiler, h is the above-mentioned enthalpy, h ₀ is the feed water enthalpy, and B is the black liquor flow rate. , H is the calorific value per flow rate of black liquor.

After that, the boiler state determination unit 47 grasps the boiler efficiency in a normal state (almost no dirt) in which the heat transfer unit can appropriately perform the original heat exchange, so that the boiler efficiency η, Is used to determine the contamination coefficient α which represents the contamination state of the boiler.

α = (− η) / ... (2) This stain coefficient α is expressed as 0 to 1, and when 0, it is normal and there is no stain, that is, when stain is 0% and 1 is 10
It means 0%.

After the fouling coefficient α has been obtained by the boiler state determination unit 47 as described above, the fouling coefficient α is sent to the soot blow time interval determining means 48. The soot blow time interval determining means 48 changes the time interval data of each lance in the table memory of the lance determining unit 45 based on the dirt coefficient α, for example, corresponding to 0 to 1 of the dirt coefficient α. The time interval coefficient T to be calculated is obtained.

T = (1−α) / α (3) After the time interval coefficient T is obtained in this way, the sootblow time interval determining means 48 sends the time interval coefficient T to the lance determining unit 45. Here, the lance determination unit 45 multiplies the time interval of the table memory by the coefficient T to obtain the change time interval data of each lance, and stores this as the change data in the area corresponding to each lance of the table memory. . Incidentally, FIG. 3B shows the time interval data changed when the dirt coefficient α = 0.25, and FIG. 3C shows the time interval data changed when the dirt coefficient α = 0.75. . Therefore, FIG. 3 (b) shows that the lance spraying time interval is three times that in the normal state because the soiling is very severe, and FIG. 3 (c) has less soiling contrary to FIG. Drive and control the soot brolance at 1/3 time intervals.

Therefore, according to the configuration of the embodiment as described above, after obtaining the thermal efficiency from the process signal, the thermal efficiency is converted into the contamination coefficient to determine the contamination state of the heat transfer portion.
It is possible to determine the dirty state of the heat transfer section by a simple calculation. Also, this dirt state, that is, the dirt coefficient is converted into a time interval coefficient, and this conversion coefficient is multiplied by the time interval data of each predetermined lance to obtain the time interval of each soot blow lance, and the correspondence is performed based on this time interval. Since the soot blow lance is driven and controlled, the dust can be removed at an appropriate time interval according to the dirt state. Therefore, since the driving time of the soot blow lance is changed according to the dirty state of the heat transfer section, the dust adhering to the heat transfer section can be surely removed, the steam generation efficiency in the boiler can be increased, and it becomes a raw material of the chemical agent. The quality of smelt can be improved.

In the above embodiment, the time interval data of all soot brolances are changed based on the state of the process, but the process signal is captured for each of the super heater 21, the main body bank 22 and the economizer 23 that constitute the heat transfer section. By calculating the heat conversion efficiency and calculating the dirt factor, dust can be removed by changing the time interval data in units of soot blow lance installed for each superheater 21, main body bank 22 and economizer 23. It is possible. This makes it possible to change the time interval of the soot blow lance as appropriate according to the dirty state of each part of the heat transfer section, and to always operate the plant in an optimal state, which greatly contributes to energy saving.

Further, although the sequence and the lance NO are used as the sequence data in the above embodiment, only the lance NO data may be used. In addition, the present invention can be modified in various ways without departing from the scope of the invention.

[Effects of the Invention] As described in detail above, according to the present invention, the driving time of the soot blow lance can be appropriately changed according to the dirty state of the heat transfer section, and thus the boiler can be operated in a stable state at all times as required. It is possible to provide a soot blow control device for a boiler, which can efficiently collect the generated products and contribute greatly to energy saving.

[Brief description of drawings]

1 to 3 are shown for explaining an embodiment of a soot blow control device for a boiler according to the present invention, and FIG. 1 is a schematic configuration diagram of a pulp manufacturing plant to which the device of the present invention is applied, FIG. 2 is a block diagram of a soot blow control device which is the gist of the present invention, FIG. 3 is a table data diagram showing time interval data that changes according to the state of dirt, and FIG. 4 is a block diagram of a conventional device, FIG. FIG. 6 is a table data diagram showing time interval data in a conventional device. 11 …… Recovery boiler, 21 …… Super heater, 22 …… Main body bank, 23 …… Economizer, 31a, 31b,…, 31n …… Soot blow lance, 32, 33 …… Measuring sensor, 40 …… Soot blow control device, 41 ...... Timer, 42 ...... Soot blow drive control means, 43 ...... Dirt state time determination means, 44 ...... Lance data registration section, 45 ...... Lance determination section, 46 ...... Soot blow start command section, 47 ...... Boiler state determination Part, 48 ... Means for determining the soot blow time interval.

Claims (3)

(57) [Claims] 1. A soot blow control device for a boiler, wherein a plurality of soot blow lances are installed toward a heat transfer section provided in a boiler, and these soot blow lances are sequentially operated to remove dust adhering to the heat transfer section. A clocking means for measuring a clock, and the spray sequence data and time interval data of the plurality of soot brolans are stored in advance in a table memory,
A soot blow drive control means for accumulating signals from the time counting means, and sending a drive control signal to the next soot blow lance based on the spraying order data when the integrated time reaches the time interval of the soot blow lance currently being driven. A heat efficiency calculation means for receiving a process signal from a sensor installed at a predetermined position of the heat transfer part to obtain a heat efficiency, and a dirt for determining a dirt coefficient of the heat transfer part based on the heat efficiency calculated by the heat efficiency calculation means. A boiler comprising: coefficient determining means; and soot blow time interval determining means for changing time interval data in the table memory of the soot blow drive control means based on the dirt coefficient determined by the dirt coefficient determining means. Soot blow control device. 2. The soot-blowing drive control means integrates the signals from the time-measuring means, and codes the soot-blowing NO to be driven next when the integrated time reaches the time interval of the soot-blowing currently being driven. And a soot blow start command section for receiving a code from the lance decision section and giving a drive control signal to the soot blow lance of the soot blow lance NO corresponding to the code. A soot blow control device for a boiler according to item 1. 3. The soot-blowing time interval determining means converts the dirt factor into a time interval coefficient and multiplies the time interval coefficient by the time interval data to change the soot blow lance into new time interval data. A soot blow control device for a boiler according to claim 1.